Method and apparatus for data capture and analysis system

ABSTRACT

Content leaving a local network can be captured and indexed so that queries can be performed on the captured data. In one embodiment, the present invention comprises an apparatus that connects to a network. In one embodiment, this apparatus includes a network interface module to connect the apparatus to a network, a packet capture module to intercept packets being transmitted on the network, an object assembly module to reconstruct objects being transmitted on the network from the intercepted packets, an object classification module to determine the content in the reconstructed objects, and an object store module to store the objects. This apparatus can also have a user interface to enable a user to search objects stored in the object store module.

PRIORITY AND RELATED MATTERS

This application is a continuation (and claims the benefit of priorityunder 35 U.S.C. §120) of U.S. application Ser. No. 10/815,240, filedMar. 30, 2004, entitled “METHOD AND APPARATUS FOR DATA CAPTURE ANDANALYSIS SYSTEM,” Inventor(s) Erik de la Iglesia, et al, which claimsthe priority benefit of U.S. Provisional Application No. 60/528,643,entitled “METHOD AND APPARATUS FOR DATA CAPTURE AND ANALYSIS SYSTEM,”filed Dec. 10, 2003. The disclosure of the prior applications isconsidered part of (and is incorporated by reference in) the disclosureof this application.

FIELD OF THE INVENTION

The present invention relates to computer networks, and in particular,to capturing and organizing data in a computer network.

BACKGROUND

Computer networks and systems have become indispensable tools for modernbusiness. Modern enterprises use such networks for communications andfor storage. The information and data stored on the network of abusiness enterprise is often a highly valuable asset. Modern enterprisesuse numerous tools to keep outsiders, intruders, and unauthorizedpersonnel from accessing valuable information stored on the network.These tools include firewalls, intrusion detection systems, and packetsniffer devices. However, once an intruder has gained access tosensitive content, there is no network device that can prevent theelectronic transmission of the content from the network to outside thenetwork. Similarly, there is no network device that can analyze the dataleaving the network to monitor for policy violations, and make itpossible to track down information leaks. What is needed is acomprehensive system to capture, store, and analyze all datacommunicated using the enterprises network.

SUMMARY OF THE INVENTION

Content leaving a local network can be captured and indexed so thatqueries can be performed on the captured data. In one embodiment, thepresent invention comprises an apparatus that connects to a network. Inone embodiment, this apparatus includes a network interface module toconnect the apparatus to a network, a packet capture module to interceptpackets being transmitted on the network, an object assembly module toreconstruct objects being transmitted on the network from theintercepted packets, an object classification module to determine thecontent in the reconstructed objects, and an object store module tostore the objects. This apparatus can also have a user interface toenable a user to search objects stored in the object store module.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings in which likereference numerals refer to similar elements and in which:

FIG. 1 is a block diagram illustrating a computer network connected tothe Internet;

FIG. 2 is a block diagram illustrating one configuration of a capturesystem according to one embodiment of the present invention;

FIG. 3 is a block diagram illustrating the capture system according toone embodiment of the present invention;

FIG. 4 is a block diagram illustrating an object assembly moduleaccording to one embodiment of the present invention;

FIG. 5 is a block diagram illustrating an object store module accordingto one embodiment of the present invention; and

FIG. 6 is a block diagram illustrating an example hardware architecturefor a capture system according to one embodiment of the presentinvention.

DETAILED DESCRIPTION

Although the present system will be discussed with reference to variousillustrated examples, these examples should not be read to limit thebroader spirit and scope of the present invention. Some portions of thedetailed description that follows are presented in terms of algorithmsand symbolic representations of operations on data within a computermemory. These algorithmic descriptions and representations are the meansused by those skilled in the computer science arts to most effectivelyconvey the substance of their work to others skilled in the art. Analgorithm is here, and generally, conceived to be a self-consistentsequence of steps leading to a desired result. The steps are thoserequiring physical manipulations of physical quantities. Usually, thoughnot necessarily, these quantities take the form of electrical ormagnetic signals capable of being stored, transferred, combined,compared and otherwise manipulated.

It has proven convenient at times, principally for reasons of commonusage, to refer to these signals as bits, values, elements, symbols,characters, terms, numbers or the like. It should be borne in mind,however, that all of these and similar terms are to be associated withthe appropriate physical quantities and are merely convenient labelsapplied to these quantities. Unless specifically stated otherwise, itwill be appreciated that throughout the description of the presentinvention, use of terms such as “processing”, “computing”,“calculating”, “determining”, “displaying” or the like, refer to theaction and processes of a computer system, or similar electroniccomputing device, that manipulates and transforms data represented asphysical (electronic) quantities within the computer system's registersand memories into other data similarly represented as physicalquantities within the computer system memories or registers or othersuch information storage, transmission or display devices.

As indicated above, one embodiment of the present invention isinstantiated in computer software, that is, computer readableinstructions, which, when executed by one or more computerprocessors/systems, instruct the processors/systems to perform thedesignated actions. Such computer software may be resident in one ormore computer readable media, such as hard drives, CD-ROMs, DVD-ROMs,read-only memory, read-write memory and so on. Such software may bedistributed on one or more of these media, or may be made available fordownload across one or more computer networks (e.g., the Internet).Regardless of the format, the computer programming, rendering andprocessing techniques discussed herein are simply examples of the typesof programming, rendering and processing techniques that may be used toimplement aspects of the present invention. These examples should in noway limit the present invention, which is best understood with referenceto the claims that follow this description.

Networks

FIG. 1 illustrates a simple prior art configuration of a local areanetwork (LAN) 10 connected to the Internet 12. Connected to the LAN 102are various components, such as servers 14, clients 16, and switch 18.There are numerous other known networking components and computingdevices that can be connected to the LAN 10. The LAN 10 can beimplemented using various wireline or wireless technologies, such asEthernet and 802.11b. The LAN 10 may be much more complex than thesimplified diagram in FIG. 1, and may be connected to other LANs aswell.

In FIG. 1, the LAN 10 is connected to the Internet 12 via a router 20.This router 20 can be used to implement a firewall, which are widelyused to give users of the LAN 10 secure access to the Internet 12 aswell as to separate a company's public Web server (can be one of theservers 14) from its internal network, i.e., LAN 10. In one embodiment,any data leaving the LAN 10 towards the Internet 12 must pass throughthe router 12. However, there the router 20 merely forwards packets tothe Internet 12. The router 20 cannot capture, analyze, and searchablystore the content contained in the forwarded packets.

One embodiment of the present invention is now illustrated withreference to FIG. 2. FIG. 2 shows the same simplified configuration ofconnecting the LAN 10 to the Internet 12 via the router 20. However, inFIG. 2, the router 20 is also connected to a capture system 22. In oneembodiment, the router 12 splits the outgoing data steam, and forwardsone copy to the Internet 12 and the other copy to the capture system 22.

There are various other possible configurations. For example, the router12 can also forward a copy of all incoming data to the capture system 22as well. Furthermore, the capture system 22 can be configuredsequentially in front of, or behind the router 20, however this makesthe capture system 22 a critical component in connecting to the Internet12. In systems where a router 12 is not used at all, the capture systemcan be interposed directly between the LAN 10 and the Internet 12. Inone embodiment, the capture system 22 has a user interface accessiblefrom a LAN-attached device, such as a client 16.

In one embodiment, the capture system 22 intercepts all data leaving thenetwork. In other embodiments, the capture system can also intercept alldata being communicated inside the network 10. In one embodiment, thecapture system 22 reconstructs the documents leaving the network 10, andstores them in a searchable fashion. The capture system 22 can then beused to search and sort through all documents that have left the network10. There are many reasons such documents may be of interest, includingnetwork security reasons, intellectual property concerns, corporategovernance regulations, and other corporate policy concerns.

Capture System

One embodiment of the present invention is now described with referenceto FIG. 3. FIG. 3 shows one embodiment of the capture system 22 in moredetail. The capture system 22 is also sometimes referred to as a contentanalyzer, content or data analysis system, and other similar names. Inone embodiment, the capture system 22 includes a network interfacemodule 24 to receive the data from the network 10 or the router 20. Inone embodiment, the network interface module 24 is implemented using oneor more network interface cards (NIC), e.g., Ethernet cards. In oneembodiment, the router 20 delivers all data leaving the network to thenetwork interface module 24.

The captured raw data is then passed to a packet capture module 26. Inone embodiment, the packet capture module 26 extracts data packets fromthe data stream received from the network interface module 24. In oneembodiment, the packet capture module 26 reconstructs Ethernet packetsfrom multiple sources to multiple destinations for the raw data stream.

In one embodiment, the packets are then provided the object assemblymodule 28. The object assembly module 28 reconstructs the objects beingtransmitted by the packets. For example, when a document is transmitted,e.g. as an email attachment, it is broken down into packets according tovarious data transfer protocols such as Transmission ControlProtocol/Internet Protocol (TCP/IP) and Ethernet. The object assemblymodule 28 can reconstruct the document from the captured packets.

One embodiment of the object assembly module 28 is now described in moredetail with reference to FIG. 4. When packets first enter the objectassembly module, they are first provided to a reassembler 36. In oneembodiment, the reassembler 36 groups—assembles—the packets into uniqueflows. For example, a flow can be defined as packets with identicalSource IP and Destination IP addresses as well as identical TCP Sourceand Destination Ports. That is, the reassembler 36 can organize a packetstream by sender and recipient.

In one embodiment, the reassembler 36 begins a new flow upon theobservation of a starting packet defined by the data transfer protocol.For a TCP/IP embodiment, the starting packet is generally referred to asthe “SYN” packet. The flow can terminate upon observation of a finishingpacket, e.g., a “Reset” or “FIN” packet in TCP/IP. If now finishingpacket is observed by the reassembler 36 within some time constraint, itcan terminate the flow via a timeout mechanism. In an embodiment usingthe TPC protocol, a TCP flow contains an ordered sequence of packetsthat can be assembled into a contiguous data stream by the reassembler36. Thus, in one embodiment, a flow is an ordered data stream of asingle communication between a source and a destination.

The flow assembled by the reassembler 36 can then be provided to aprotocol demultiplexer (demux) 38. In one embodiment, the protocol demux38 sorts assembled flows using the TCP Ports. This can includeperforming a speculative classification of the flow contents based onthe association of well-known port numbers with specified protocols. Forexample, Web Hyper Text Transfer Protocol (HTTP) packets—i.e., Webtraffic—are typically associated with port 80, File Transfer Protocol(FTP) packets with port 20, Kerberos authentication packets with port88, and so on. Thus in one embodiment, the protocol demux 38 separatesall the different protocols in one flow.

In one embodiment, a protocol classifier 40 also sorts the flows inaddition to the protocol demux 38. In one embodiment, the protocolclassifier 40—operating either in parallel or in sequence with theprotocol demux 38—applies signature filters to the flows to attempt toidentify the protocol based solely on the transported data. Furthermore,the protocol demux 38 can make a classification decision based on portnumber, which is subsequently overridden by protocol classifier 40. Forexample, if an individual or program attempted to masquerade an illicitcommunication (such as file sharing) using an apparently benign portsuch as port 80 (commonly used for HTTP Web browsing), the protocolclassifier 40 would use protocol signatures, i.e., the characteristicdata sequences of defined protocols, to verify the speculativeclassification performed by protocol demux 38.

In one embodiment, the object assembly module 28 outputs each floworganized by protocol, which represent the underlying objects. Referringagain to FIG. 3, these objects can then be handed over to the objectclassification module 30 (sometimes also referred to as the “contentclassifier”) for classification based on content. A classified flow maystill contain multiple content objects depending on the protocol used.For example, protocols such as HTTP (Internet Web Surfing) may containover 100 objects of any number of content types in a single flow. Todeconstruct the flow, each object contained in the flow is individuallyextracted, and decoded, if necessary, by the object classificationmodule 30.

The object classification module 30 uses the inherent properties andsignatures of various documents to determine the content type of eachobject. For example, a Word document has a signature that is distinctfrom a PowerPoint document, or an Email document. The objectclassification module 30 can extract out each individual object and sortthem out by such content types. Such classification renders the presentinvention immune from cases where a malicious user has altered a fileextension or other property in an attempt to avoid detection of illicitactivity.

In one embodiment, the object classification module 30 determineswhether each object should be stored or discarded. In one embodiment,this determination is based on a various capture rules. For example, acapture rule can indicate that Web Traffic should be discarded. Anothercapture rule can indicate that all PowerPoint documents should bestored, except for ones originating from the CEO's IP address. Suchcapture rules can be implemented as regular expressions, or by othersimilar means.

In one embodiment, the capture rules are authored by users of thecapture system 22. The capture system 22 is made accessible to anynetwork-connected machine through the network interface module 24 anduser interface 34. In one embodiment, the user interface 34 is agraphical user interface providing the user with friendly access to thevarious features of the capture system 22. For example, the userinterface 34 can provide a capture rule authoring tool that allows usersto write and implement any capture rule desired, which are then appliedby the object classification module 30 when determining whether eachobject should be stored. The user interface 34 can also providepre-configured capture rules that the user can select from along with anexplanation of the operation of such standard included capture rules. Inone embodiment, the default capture rule implemented by the objectclassification module 30 captures all objects leaving the network 10.

If the capture of an object is mandated by the capture rules, the objectclassification module 30 can also determine where in the object storemodule 32 the captured object should be stored. With reference to FIG.5, in one embodiment, the objects are stored in a content store 44memory block. Within the content store 44 are files 46 divided up bycontent type. Thus, for example, if the object classification moduledetermines that an object is a Word document that should be stored, itcan store it in the file 46 reserved for Word documents. In oneembodiment, the object store module 32 is integrally included in thecapture system 22. In other embodiments, the object store module can beexternal—entirely or in part—using, for example, some network storagetechnique such as network attached storage (NAS) and storage areanetwork (SAN).

In one embodiment, the content store is a canonical storage location,simply a place to deposit the captured objects. The indexing of theobjects stored in the content store 44 is accomplished using a tagdatabase 42. In one embodiment, the tag database 42 is a database datastructure in which each record is a “tag” that indexes an object in thecontent store 44, and contains relevant information about the storedobject. An example of a tag record in the tag database 42 that indexesan object stored in the content store 44 is set forth in Table 1:

TABLE 1 Field Name Definition MAC Address Ethernet controller MACaddress unique to each capture system Source IP Source Ethernet IPAddress of object Destination IP Destination Ethernet IP Address ofobject Source Port Source TCP/IP Port number of object Destination PortDestination TCP/IP Port number of the object Protocol IP Protocol thatcarried the object Instance Canonical count identifying object within aprotocol capable of carrying multiple data within a single TCP/IPconnection Content Content type of the object Encoding Encoding used bythe protocol carrying object Size Size of object Timestamp Time that theobject was captured Owner User requesting the capture of object (ruleauthor) Configuration Capture rule directing the capture of objectSignature Hash signature of object Tag Signature

There are various other possible tag fields, and some embodiments canomit numerous tag fields listed in Table 1. In other embodiments, thetag database 42 need not be implemented as a database; other datastructures can be used. The mapping of tags to objects can, in oneembodiment, be obtained by using unique combinations of tag fields toconstruct an object's name. For example, one such possible combinationis an ordered list of the Source IP, Destination IP, Source Port,Destination Port, Instance and Timestamp. Many other such combinationsincluding both shorter and longer names are possible. In anotherembodiment, the tag can contain a pointer to the storage location wherethe indexed object is stored.

Referring again to FIG. 3, in one embodiment, the objects and tagsstored in the object store module 32 can be interactively queried by auser via the user interface 34. In one embodiment the user interface caninteract with a web server (not shown) to provide the user withWeb-based access to the capture system 22. The objects in the contentstore module 32 can thus be searched for specific textual or graphicalcontent using exact matches, patterns, keywords, and various otheradvanced attributes.

For example, the user interface 34 can provide a query-authoring tool(not shown) to enable users to create complex searches of the objectstore module 32. These search queries can be provided to a data miningengine (not shown) that parses the queries, scans the tag database 42,and retrieves the found object from the content store 44. Then, theseobjects that matched the specific search criteria in the user-authoredquery can be counted and displayed to the user by the user interface 34.

Searches can also be scheduled to occur at specific times or at regularintervals, that is, the user interface 34 can provide access to ascheduler (not shown) that can periodically execute specific queries.Reports containing the results of these searches can be made availableto the user at a later time, mailed to the administrator electronically,or used to generate an alarm in the form of an e-mail message, page,syslog or other notification format.

In several embodiments, the capture system 22 has been described aboveas a stand-alone device. However, the capture system of the presentinvention can be implemented on any appliance capable of capturing andanalyzing data from a network. For example, the capture system 22described above could be implemented on one or more of the servers 14 orclients 16 shown in FIG. 1. The capture system 22 can interface with thenetwork 10 in any number of ways, including wirelessly.

In one embodiment, the capture system 22 is an appliance constructedusing commonly available computing equipment and storage systems capableof supporting the software requirements. In one embodiment, illustratedby FIG. 6, the hardware consists of a capture entity 46, a processingcomplex 48 made up of one or more processors; a memory complex 50 madeup of one or more memory elements such as RAM and ROM, and storagecomplex 52, such as a set of one or more hard drives or other digital oranalog storage means. In another embodiment, the storage complex 52 isexternal to the capture system 22, as explained above. In oneembodiment, the memory complex stored software consisting of anoperating system for the capture system device 22, a capture program,and classification program, a database, a filestore, an analysis engineand a graphical user interface.

Thus, a capture system and content analyzer have been described. In theforgoing description, various specific values were given names, such as“packets,” and various specific modules, such as the “object assemblymodule” and “object store module” have been described. However, thesenames are merely to describe and illustrate various aspects of thepresent invention, and in no way limit the scope of the presentinvention. Furthermore, various modules, such as the object store module32 and the object classification module 30 in FIG. 3, can be implementedas software or hardware modules, or without dividing theirfunctionalities into modules at all. The present invention is notlimited to any modular architecture either in software or in hardware,whether described above or not.

What is claimed is:
 1. A method, comprising: receiving a flow of packetsin a network; applying a filter to the flow in order to identify aprotocol for the flow; extracting a plurality of objects associated withflow; determining a content type for each of the objects based on asignature identified within the objects; and providing a user interfaceto enable a user to use a query to search for stored objects, whereinthe query includes search criteria used to identify certain objects thatmatch the search criteria, wherein a particular search is scheduled fora recurring time interval and includes a particular search query withselected terms, and wherein certain results of the particular searchtrigger an e-mail message to be sent to an administrator.
 2. The methodof claim 1, wherein the determining includes identifying maliciouscontent based on a file extension associated with the flow.
 3. Themethod of claim 1, further comprising: determining whether the object isto be stored or discarded based on a plurality of capture rules.
 4. Themethod of claim 3, further comprising: providing the user interface forauthoring the capture rules that designate which objects is to be storedor discarded.
 5. The method of claim 1, further comprising: storing atleast some of the objects in a content store, which is indexed by a tagdatabase in which each record has an associated tag that indexes acorresponding object.
 6. The method of claim 1, further comprising:receiving a search query for particular content associated with theflow.
 7. The method of claim 1, further comprising: providing at leastsome of the objects in response to the search query.
 8. The method ofclaim 1, further comprising: providing at least some of the packets toan object assembly module, which is configured to reconstruct an elementoriginally sought for propagation in the network.
 9. The method of claim1, wherein the packets are reassembled into unique flows based on asource Internet Protocol (IP) address and a destination IP address. 10.The method of claim 1, wherein the packets form an e-mail.
 11. Themethod of claim 1, wherein the packets form a document.
 12. The methodof claim 1, wherein a network interface receives the flow of packets.13. The method of claim 12, wherein the network interface comprises aplurality of network interface cards (NICs).
 14. The method of claim 12,wherein the network interface comprises a plurality of Ethernet cards.15. Logic encoded in one or more non-transitory media that includes codefor execution and when executed by a processor operable to performoperations comprising: receiving a flow of packets in a network;applying a filter to the flow in order to identify a protocol for theflow; extracting a plurality of objects associated with flow;determining a content type for each of the objects based on a signatureidentified within the objects; and providing a user interface to enablea user to use a query to search for stored objects, wherein the queryincludes search criteria used to identify certain objects that match thesearch criteria, wherein a particular search is scheduled for arecurring time interval and includes a particular search query withselected terms, and wherein certain results of the particular searchtrigger an e-mail message to be sent to an administrator.
 16. The logicof claim 15, wherein the determining includes identifying maliciouscontent based on a file extension associated with the flow, and whereina determination is made as to whether the object is to be stored ordiscarded based on a plurality of capture rules, and wherein the userinterface is provided for authoring the capture rules that designatewhich objects is to be stored or discarded.
 17. The media of claim 15,wherein the determining includes identifying malicious content based ona file extension associated with the flow.
 18. The media of claim 15,the operations further comprising: determining whether the object is tobe stored or discarded based on a plurality of capture rules.
 19. Themedia of claim 18, the operations further comprising: providing the userinterface for authoring the capture rules that designate which objectsis to be stored or discarded.
 20. The media of claim 15, the operationsfurther comprising: storing at least some of the objects in a contentstore, which is indexed by a tag database in which each record has anassociated tag that indexes a corresponding object.
 21. The media ofclaim 15, the operations further comprising: receiving a search queryfor particular content associated with the flow.
 22. The media of claim15, the operations further comprising: providing at least some of theobjects in response to the search query.
 23. The media of claim 15, theoperations further comprising: providing at least some of the packets toan object assembly module, which is configured to reconstruct an elementoriginally sought for propagation in the network.
 24. The media of claim15, wherein the packets are reassembled into unique flows based on asource Internet Protocol (IP) address and a destination IP address. 25.The media of claim 15, wherein a network interface receives the flow ofpackets, and wherein the network interface comprises a plurality ofnetwork interface cards (NICs) or a plurality of Ethernet cards.
 26. Anapparatus, comprising: a memory element; and a processor coupled to thememory element, wherein the apparatus is configured for: receiving aflow of packets in a network; applying a filter to the flow in order toidentify a protocol for the flow; extracting a plurality of objectsassociated with flow; determining a content type for each of the objectsbased on a signature identified within the objects; and providing a userinterface to enable a user to use a query to search for stored objects,wherein the query includes search criteria used to identify certainobjects that match the search criteria, wherein a particular search isscheduled for a recurring time interval and includes a particular searchquery with selected terms, and wherein certain results of the particularsearch trigger an e-mail message to be sent to an administrator.
 27. Theapparatus of claim 26, wherein the determining includes identifyingmalicious content based on a file extension associated with the flow.28. The apparatus of claim 26, wherein the apparatus is furtherconfigured for: determining whether the object is to be stored ordiscarded based on a plurality of capture rules.
 29. The apparatus ofclaim 28, wherein the apparatus is further configured for: providing theuser interface for authoring the capture rules that designate whichobjects is to be stored or discarded.
 30. The apparatus of claim 26,wherein the apparatus is further configured for: storing at least someof the objects in a content store, which is indexed by a tag database inwhich each record has an associated tag that indexes a correspondingobject.
 31. The apparatus of claim 26, wherein the apparatus is furtherconfigured for: receiving a search query for particular contentassociated with the flow.
 32. The apparatus of claim 26, wherein theapparatus is further configured for: providing at least some of theobjects in response to the search query.
 33. The apparatus of claim 26,wherein the apparatus is further configured for: providing at least someof the packets to an object assembly module, which is configured toreconstruct an element originally sought for propagation in the network.34. The apparatus of claim 26, wherein the packets are reassembled intounique flows based on a source Internet Protocol (IP) address and adestination IP address.
 35. The apparatus of claim 26, wherein a networkinterface receives the flow of packets, and wherein the networkinterface comprises a plurality of network interface cards (NICs) or aplurality of Ethernet cards.